The SecuRam ProLogic B01 locks are badged as the industry’s only Bluetooth-packing lock for safes that can be paired with smartphones.

The researchers (@somersetrecon) found replay design flaws they surmised could not easily be patched, which permit a “fully-automated” remote attack against the locks that worked over distances of up to 100 yards (90 metres).

“The end result was a fully-automated attack that allows us to remotely compromise any Prologic B01 lock up to 100 yards away,” the team says.

“… attackers can execute cheap and practical attacks to locate and map these devices, know when they are unlocked over Bluetooth low energy (BLE), and extract the PIN with which they were unlocked.

“We have contacted SecuRam about this vulnerability, but since these devices are not capable of over-the-air firmware updates, it does not look promising that they will be patched.”

Attackers could identify the devices by wardriving with an Ubertooth One and a 5dBi antenna capable of detecting the locks from the maximum 90 metres distance.

From there gear can be placed to automatically listen and capture safe unlock commands when it is broadcast by victims, handing attackers the relevant unlock PIN.

The team in a paper Bluetooth Attacks on Commercial-Grade Electronic Locks [PDF] reported holes in the lock’s wireless protocol which they say likely applies to other similar locks “regardless of commercial-grading”.

They recommend users do not use the lock until the problems are fixed.

It follows research published in August in which a dozen Bluetooth locks could be easily hacked using similar kit.